Pseudodeterminants and perfect square spanning tree counts

The pseudodeterminant $\textrm{pdet}(M)$ of a square matrix is the last nonzero coefficient in its characteristic polynomial; for a nonsingular matrix, this is just the determinant. If $\partial$ is a symmetric or skew-symmetric matrix then $\textrm{pdet}(\partial\partial^t)=\textrm{pdet}(\partial)^2$. Whenever $\partial$ is the $k^{th}$ boundary map of a self-dual CW-complex $X$, this linear-algebraic identity implies that the torsion-weighted generating function for cellular $k$-trees in $X$ is a perfect square. In the case that $X$ is an \emph{antipodally} self-dual CW-sphere of odd dimension, the pseudodeterminant of its $k$th cellular boundary map can be interpreted directly as a torsion-weighted generating function both for $k$-trees and for $(k-1)$-trees, complementing the analogous result for even-dimensional spheres given by the second author. The argument relies on the topological fact that any self-dual even-dimensional CW-ball can be oriented so that its middle boundary map is skew-symmetric.Comment: Final version; minor revisions. To appear in Journal of Combinatoric

Towards a Comprehensive Survey of C3 and C4 Photosynthetic Pathways in Cyperaceae

Members of the family Cyperaceae were surveyed by original observation and from the literature to assess the distribution of C3 and C4 photosynthetic pathways in the family. All 107 genera were included in the current sample, with 91 genera assessed as consistently C3 and 11 genera as C4. The genera Abildgaardia, Cyperus, Eleocharis, Fimbristylis, and Rhynchospora are variable for this trait. Of the total number (1474) of specific (1406) and infraspecific (68) taxa sampled, 938 taxa (63%) are C3, 527 taxa (36%) are C4, and nine species of Eleocharis are debatably intermediate or variable in pathway. Some data suggesting further infrageneric variation in photosynthetic pathways are discussed. The ‘‘one cell distant criterion’’ accurately predicts C4 pathway in sedges, except in Eleocharis. Distribution and variability of photosynthetic pathways in Eleocharis are discussed. Photosynthetic pathway was found to be a useful taxonomic marker in Cyperaceae, despite variability in this trait at various taxonomic levels and the apparently multiple origin of C4 photosynthesis within the family. A checklist of 3395 records of C3 and C4 sedges is presented

Reinstatement and revision of the genus Chaetospora (Cyperaceae: Schoeneae)

Three species are recognised in a new circumscription of the genus Chaetospora R.Br. Chaetospora is lectotypified on C. curvifolia R.Br. A new combination, Chaetospora subbulbosa (Benth.) K.L.Wilson & R.L.Barrett is made for Schoenus subbulbosus Benth. Lectotypes are also selected for Chaetospora aurata Nees, Chaetospora curvifolia R.Br., Chaetospora turbinata R.Br., Elynanthus capitatus Nees, Schoenus subbulbosus Benth., Schoenus subg. Pseudomesomelaena Kük. and Schoenus sect. Sphaerocephali Benth. Two species are endemic to south-western Australia, while the third is endemic to south-eastern Australia. Full descriptions, illustrations and a key to species are provided. All species have anatomy indicative of C3 photosynthetic-type

Netrostylis, a new genus of Australasian Cyperaceae removed from Tetraria

A new genus, Netrostylis R.L.Barrett, J.J.Bruhl & K.L.Wilson is described for Australasian species previously known as Tetraria capillaris (F.Muell.) J.M.Black (Cyperacea tribe Schoeneae). The genus is restricted to southern and eastern Australia, and the North Island of New Zealand. Two new combinations are made: Netrostylis capillaris (F.Muell.) R.L.Barrett, J.J.Bruhl & K.L.Wilson and Netrostylis halmaturina (J.M.Black) R.L.Barrett, J.J.Bruhl & K.L.Wilson. Netrostylis is a member of the Lepidosperma Labill. Clade

Use of automated response systems in the small sized class

An interactive demonstration of various teaching methods using Remote Response Systems (Automated Response Systems, Personal Response Systems, Clickers ) as they were applied to the small sized class (\u3c 20 students). Most of the research with clickers has been in large classes. The methods used (peer instruction, group discussion, and simple polling with contingency teaching) will be demonstrated and results of the initial study with a class of 14 students will be presented. Internet access for all participants (local computers, laptops, or phones) will be necessary for this activity

Monitoring wildlife-vehicle collisions: analysis and cost-benefit of escape ramps for deer and elk on U.S. Highway 550

Prepared for: Colorado Department of Transportation, Division of Transportation Development, Applied Research and Innovation Branch. Prepared in cooperation with the US Department of Transportation, Federal Highway Administration.Report No. CDOT-2015-5.May 2015.Includes bibliographical references (pages 35-37).Wildlife fencing along highways can lower wildlife-vehicle collision rates by excluding animals from the road right-of-way. Still, animals can breach fencing and end up trapped within the fencing along the highway right-of-way, exposing wildlife and motorists to the risk of collision. Wildlife escape ramps are designed to allow trapped animals safe passage out of the right-of-way. Few recommendations exist on effective design of escape ramps and monitoring data are limited. We investigated the usage levels, escape success, wildlife-vehicle collisions, and design of 11 escape ramps and two escape jumps along an eight-mile stretch of U.S. Highway 550 near Ridgway, Colorado. Our goals were to 1) relate usage levels and escape success to ER structure design and its surrounding environmental characteristics, 2) describe the animal use of ER in the study area, 3) conduct a cost-benefit analysis for escape ramp construction and 4) provide recommendations regarding ER design and WVC based on data collected.Study No: 032.47

Lepidosperma prospectum (Cyperaceae), a new species from Sydney coastal heath and notes on usage of sword sedges

Lepidosperma prospectum G.T.Plunkett & R.L.Barrett (Cyperaceae tribe Schoeneae) is here described as a new species in the Sydney region of New South Wales. It is highly restricted in distribution, occurring at Manly (Sydney Harbour National Park), Kamay Botany Bay National Park and Royal National Park in dense coastal shrublands behind coastal cliffs. These locations are within the traditional lands of the Gamaragal, Gweagal and Dharawal people respectively. Joseph Banks and Daniel Solander were the first Europeans to explore the flora of New South Wales in 1770 around Botany Bay but they did not collect this species. Lepidosperma prospectum is superficially similar to L. sieberi Kunth, which occurs in adjacent habitats, but molecular data have shown that it is more closely allied to Western Australian species. A brief review of recorded indigenous and European knowledge and utilisation of the genus Lepidosperma Labill. is presented to highlight the varied uses of the genus

Phylogeny of Abildgaardieae (Cyperaceae) Inferred from ITS and trnL–F Data

Within the tribe Abildgaardieae, the relationships between Fimbristylis and its relatives have not been certain, and the limits of Fimbristylis have been unclear, with Bulbostylis and Abildgaardia variously combined with it and each other. The relationships and limits of tribes Abildgaardieae and Arthrostylideae and their genera were evaluated across 49 representative species using parsimony and maximum likelihood analyses of ITS (nuclear ribosomal) and trnL–F (plastid) DNA sequence data separately and combined. The evolutionary reconstructions derived from sequences of cpDNA and nrDNA disagree about the position of tribe Arthrostylideae relative to Abildgaardieae; Arthrostylis and Actinoschoenus are either nested within Abildgaardieae (trnL–F data) or very closely related to this tribe (ITS data). The reconstructions also disagree about the monophyly of genus Abildgaardia (excluding A. vaginata). Crosslandia and A. vaginata form a clade that is nested within Fimbristylis. Bulbostylis is monophyletic and clearly separated from Fimbristylis. Further sampling of taxa and characters is needed to resolve and/or strengthen support for some of these ‘‘deep’’ and fine-scale relationships

Genetic associations with childhood brain growth, defined in two longitudinal cohorts

Genome-wide association studies (GWASs) are unraveling the genetics of adult brain neuroanatomy as measured by cross-sectional anatomic magnetic resonance imaging (aMRI). However, the genetic mechanisms that shape childhood brain development are, as yet, largely unexplored. In this study we identify common genetic variants associated with childhood brain development as defined by longitudinal aMRI. Genome-wide single nucleotide polymorphism (SNP) data were determined in two cohorts: one enriched for attention-deficit/hyperactivity disorder (ADHD) (LONG cohort: 458 participants; 119 with ADHD) and the other from a population-based cohort (Generation R: 257 participants). The growth of the brain's major regions (cerebral cortex, white matter, basal ganglia, and cerebellum) and one region of interest (the right lateral prefrontal cortex) were defined on all individuals from two aMRIs, and a GWAS and a pathway analysis were performed. In addition, association between polygenic risk for ADHD and brain growth was determined for the LONG cohort. For white matter growth, GWAS meta-analysis identified a genome-wide significant intergenic SNP (rs12386571, P = 9.09 × 10-9 ), near AKR1B10. This gene is part of the aldo-keto reductase superfamily and shows neural expression. No enrichment of neural pathways was detected and polygenic risk for ADHD was not associated with the brain growth phenotypes in the LONG cohort that was enriched for the diagnosis of ADHD. The study illustrates the use of a novel brain growth phenotype defined in vivo for further study

Gut microbiota modulation of chemotherapy efficacy and toxicity

Evidence is growing that the gut microbiota modulates the host response to chemotherapeutic drugs, with three main clinical outcomes: facilitation of drug efficacy; abrogation and compromise of anticancer effects; and mediation of toxicity. The implication is that gut microbiota are critical to the development of personalized cancer treatment strategies and, therefore, a greater insight into prokaryotic co-metabolism of chemotherapeutic drugs is now required. This thinking is based on evidence from human, animal and in vitro studies that gut bacteria are intimately linked to the pharmacological effects of chemotherapies (5-fluorouracil, cyclophosphamide, irinotecan, oxaliplatin, gemcitabine, methotrexate) and novel targeted immunotherapies such as anti-PD-L1 and anti-CLTA-4 therapies. The gut microbiota modulate these agents through key mechanisms, structured as the 'TIMER' mechanistic framework: Translocation, Immunomodulation, Metabolism, Enzymatic degradation, and Reduced diversity and ecological variation. The gut microbiota can now, therefore, be targeted to improve efficacy and reduce the toxicity of current chemotherapy agents. In this Review, we outline the implications of pharmacomicrobiomics in cancer therapeutics and define how the microbiota might be modified in clinical practice to improve efficacy and reduce the toxic burden of these compounds